While networks are evolving towards broadband and mobile access, the 3rd generation partnership program (3GPP) organization proposes a long term evolution (LTE) solution in Release 8, and proposes a long term evolution-advanced (LTE-Advanced) solution in subsequent Release 10, to address aspects of mobile access networks. The coordinated multipoint (CoMP) transmission technology is one key focus of the research on LTE-Advanced. Currently, the CoMP technology mainly has four application scenarios (Scenario), where scenario 1 and scenario 2 are coordinated multipoint transmission between macro cells in a homogeneous network (Homnet), and scenario 3 and scenario 4 are coordinated multipoint transmission between a macro cell and a micro cell in a heterogeneous network (Hetnet).
In the CoMP transmission technology, different transmit sources may transmit same information, for example, different transmit sources transmit a same physical broadcast channel (PBCH) or physical downlink control channel (PDSCH); or may transmit matched information, for example, different transmit sources respectively transmit a PDCCH and a physical downlink shared channel (PDSCH). This requires that different transmit sources can share a context of a same user equipment (UE) in real time, that is, it is required that different transmit sources communicate with each other within the context of the UE. In which case, a delay in communication between different transmit sources has to be reduced to microseconds (μs). However, at present, the foregoing delay requirement can only be met by interconnecting different transmit sources by means of optical fibers or high-speed microwaves. As is known to all, the practice of interconnecting by means of optical fibers or high-speed microwaves is costly, which hinders the use of the CoMP transmission technology.